Effects of elastic band resistance training on the physical and mental health of elderly individuals: A mixed methods systematic review

Objectives Elastic band resistance training in elderly individuals can improve physical fitness and promote mental health in addition to other benefits. This systematic review aimed to review, summarize, and evaluate quantitative, qualitative, and mixed methodological studies on the use of elastic band resistance training in elderly individuals, and to investigate the influence of elastic band resistance training on the physical and mental health of elderly individuals, as well as their preferences and obstacles in training. Methods A convergent separation approach was used to synthesize and integrate the results, specifically the mixed systematic review approach recommended by the Joanna Briggs Institute. The extensive search strategy included electronic database searches in the Cochrane Library, PubMed, Embase, Web of Science, Google Scholar, MEDLINE, and CINAHL. The researchers rigorously screened the literature, extracted and analyzed the data, and evaluated the quality of the included studies using the Mixed Methods Appraisal Tool (MMAT). Results Twenty-eight studies were included, of which 25 were quantitative studies, 2 were qualitative studies, and 1 was a mixed-methods study. A total of 1,697 subjects were investigated across all studies. Quantitative evidence supports the notion that elastic band resistance training can improve upper and lower limb flexibility, endurance, upper strength, physical balance, and cardiopulmonary function and enhance the mental health of elderly individuals. Participants in the qualitative study reported some preferences and obstacles with band resistance training, but most participants reported physical benefits. Conclusions Despite the heterogeneity between studies, this review is the first systematic review to comprehensively evaluate the effectiveness of elastic band resistance training in older adults. It not only shows the influence of elastic band resistance training on the physical and mental health of the elderly, but also emphasizes the preference and obstacles of elderly individuals face.


Introduction
At present, the world is facing a state of accelerated population aging, with a significant increase in the number of elderly people [1][2][3].It is estimated that between 2015 and 2050, the population of those over 60 years old will rise from 900 million to 2 billion [4].With increasing age, the body's physiological functions gradually decline, and the most obvious changes are the gradual decline in strength caused by muscle atrophy, the continuous increase in body fat content, and the loss of skeletal muscle volume [5][6][7], resulting in the occurrence of physical weakness, mobility decline, a decrease in quality of life, accidental falls, and other adverse events [8][9][10].At the same time, due to the decline in physical fitness, loneliness, depression, and other psychological problems easily occur [11][12][13], which causes a burden of care and economic burden for patients, their families, and society [14][15][16].
Improving physical activity levels has become an important part of chronic disease management strategies in elderly individuals [17][18][19].Regular physical exercise can improve physical function, enhance muscle mass and strength, improve quality of life, reduce depressive symptoms, relieve anxiety, and promote mental health [20][21][22].In addition, physical exercise not only embodies a healthy lifestyle for the elderly but also represents an important measure for countries around the world to actively cope with the aging population [23][24][25].
Physical exercise includes aerobic and resistance exercise [26,27].Resistance training is more effective than aerobic exercise in enhancing muscle strength [28][29][30].Resistance exercises, also known as strength training, include any activity that causes muscles to contract in order to increase muscle strength and functional ability [31].One of the commonly used equipment for resistance training is elastic band, which is characterized by low cost, easy access, small size and safety [32].
To date, five reviews have evaluated the effects of elastic band resistance training in older adults.A review by Daryanti et al [31] examined the effects on frail elderly people.Martins et al [32] focused only on the effects of band resistance training on muscle strength parameters.Kim et al [33] mainly studied the influence of elastic band exercise on shoulder function in elderly individuals, but did not explore the influence of resistance training on mental health.Yeun [34] investigated the influence of resistance training with an elastic band on the flexibility and balance of elderly individuals in the community, and included an intervention of resistance training with an elastic band, plus other interventions.Lin et al [35] only included quantitative studies on the effects of elastic band exercise on the physiological function of elderly individuals and did not pay attention to the effects of resistance training on mental health.
The current literature does not fully synthesize what is known in this area and lacks a mixed-approach systematic review of the effects of band resistance training on physical and mental health in elderly individuals.This systematic review is different from previous ones in two aspects.First, it evaluates the influence of elastic band resistance training on the physical and mental health of elderly individuals, as well as their preferences and obstacles faced during training.Second, the results combine quantitative and qualitative evidence.The purpose of this study was to investigate the influence of elastic band resistance training on the physical and mental health of elderly individuals, as well as their preferences and obstacles in training.

Methods
The authors followed a convergent segregated approach recommended by the JBI methodology of mixed-methods systematic reviews (MMSR).In this approach, discrete quantitative and qualitative syntheses are conducted first; then, the evidence from both syntheses is combined [36,37].The protocol for this study was registered on the PROSPERO register of systematic reviews (CRD42023387711).

Selection criteria
2.1.1.Inclusion criteria.The review included quantitative randomized controlled trials, quantitative non-randomized studies, quantitative descriptive analyses, qualitative studies, and mixed-methods studies that used elastic band resistance training as an intervention in older adults.The subjects of the study were elderly people � 60 years old with normal communication and comprehension.The application environment of elastic band resistance training is unlimited, including hospitals, communities, homes, and nursing homes.The quantitative portion of the intervention for elastic band resistance training in older adults was also reviewed.Outcome measures were physical fitness (including upper and lower limb flexibility, upper and lower limb endurance, upper and lower limb strength, body balance, cardiopulmonary function) and mental health (including scales with mental health dimensions).The qualitative component of this review considered studies that investigated the experiences and perceptions of elastic band resistance training in older adults.
2.1.2.Exclusion criteria.The exclusion criteria were (1) studies with patient populations less than 60 years of age, (2) studies in non-English languages, (3) review articles and conference abstracts, and (4) exercise interventions and other interventions (such as nutrition interventions) combined.

Search strategy
The electronic databases of the Cochrane Library, PubMed, Embase, Web of Science, Google Scholar, MEDLINE, and CINAHL were searched to identify articles that met the inclusion criteria.The search period was from the establishment of the database to December 31, 2022.When searching the database, the retrieval method of combining subject words and free words was adopted.The following keywords were used in the database search: aged, aging, agerelated, seniors, elderly, older, resistance band, elastic band, resistance rope, elastic rope, exercise, train, movement.
The first and second authors worked together to develop keywords and search strategies according to the requirements of each database.The first author independently reviewed the title and abstract of each study based on the inclusion and exclusion criteria.The first and second authors then read each full text independently and cross-checked it.Disagreements were resolved through discussion or through consultation with the third author.Meanwhile, the authors manually searched the references of the included studies to supplement unretrieved relevant literature.

Assessment of methodological quality
The first and second authors independently evaluated the quality of the included studies using the Mixed Methods Appraisal Tool (MMAT) [38].After completing the evaluation, the results were cross-checked.If there was any disagreement, it was resolved through discussion.If there was still no decision, it was submitted to the third author for negotiation.There was 100% agreement between the first and second authors on the methodological quality entries of MMAT.The fourth author verified the methodological quality assessment.

Data extraction
The authors followed the JBI method of MMSR for data extraction [36,37].The extracted data included the author(s), year of publication, country, study methods, population, aim of the study, intervention delivery, outcome measures and key findings.The first author extracted the data independently, the second author checked the accuracy of the data extraction, and the third author randomly cross-checked the data to reduce the probability of data extraction errors.In case of disagreement, the full text was reread, and the results were discussed with the fourth author to resolve differences in the extracted data.

Data synthesis and integration
The authors followed the convergent segregated approach to synthesize and integrate the data based on the JBI methodology of MMSR [36,37].Although randomized controlled trials account for the majority of quantitative studies, meta-analyses cannot be conducted due to the heterogeneity of research interventions, results, and measurements.Therefore, quantitative results are reported in narrative form, and descriptive analysis is performed.The number of available qualitative studies was too few; therefore, a narrative synthesis was used to present the findings.Finally, we used a narrative synthesis approach to integrate the evidence from the quantitative and qualitative studies.

Results
The PRISMA Flow Diagram presents the number of papers included throughout the selection process, alongside with the reasons for exclusion (Fig 1).
All studies involved elastic band resistance training in the elderly population.The duration of training is between one and 12 months, two to five times a week, for 30 to 80 minutes each time.The main outcomes measured in the quantitative studies were body balance, upper and lower limb muscle strength, endurance and flexibility, and mental health status.The qualitative study used semis-structured face-to-face interviews to focus on the experience and suggestions of the elderly on elastic band resistance training.

Upper and lower limb endurance.
A total of 18 of 25 quantitative studies evaluated the effect of elastic band resistance training on upper and lower limb endurance in older adults.Eleven studies were randomized controlled trials [40,41,43,44,49,52,53,59,60,63,64], six were non-randomized controlled trials [42,46,48,54,58,65], and one was a quantitative descriptive study [39].Sixteen of the studies assessed the effect of elastic band resistance training on upper and lower limb endurance in older adults using the 30-s arm curl test and the 30-s chair rise test [39-44, 46, 48, 49, 52, 53, 59, 60, 63-65], and two studies used the 60-s chair rise test [54,58].Of the 10 studies that used the arm curl test, only one did not observe a significant increase in arm curling after the intervention [64].In 18 studies that assessed lower limb endurance, there was a significant rise in the number of times older adults moved from sitting to standing after the intervention (p<0.05).In two of the studies [48,52], the control group also showed significant improvement in upper and lower limb endurance after the intervention.The above results indicate that elastic band resistance training helped to improve upper and lower limb endurance in elderly individuals.[48,54,58,66], and the rest were randomized controlled trials [40, 41, 43-45, 47, 49, 51-53, 63, 64].Hand grip strength was significantly enhanced after intervention in 12 studies (p<0.05)[40, 44, 45, 47, 48, 52-54, 58, 63, 64, 66], and no significant change was found in 4 studies [41,43,49,51].Overall, elastic band resistance training may have improved upper limb muscle strength in older adults.
3.3.1.4.Body balance.Seventeen of the 25 quantitative studies assessed the effect of elastic band resistance exercises on balance in older adults with varying assessment tools.Five of the studies used the functional reach test [39,41,46,49,50], which assesses balance function by measuring subjects' ability to extend their elbows forward.Four studies showed a significant improvement after the intervention (p<0.05)[39,41,46,50], but no significant change in the study of Oesen et al [49].Three studies used Berg's balance scale [50,61,63], two studies had significant changes after the intervention [50,63], and one had no significant changes [61].
Five studies used the single-leg standing test with eyes open and/or closed, two studies showed no significant change in standing time after the intervention [41,58], and three studies showed a significant increase (p<0.05)[39,60,61].Twelve studies used the up-and-go test [39, 41, 44-46, 48, 50, 52, 59, 61, 64, 66], which is used to assess balance and functional exercises and to predict fall risk in older adults, and all observed a significant reduction in measurement time after intervention except in the work of Park [39], Yu [61], Kim [64], and Sansanz-Lastra et al [66].Other studies using the Tinetti Gait and Balance test [45], the Activities-specific Balance Confidence scale [49], the Dynamic Gait Index [50], and the time required to measure a 27.7-inch step up and down [42] to assess participants' balance improved significantly after the intervention (p<0.05), in which the control group in Fahlman et al [42] also improved their balance (p<0.05).In general, elastic band resistance training could improve the balance of elderly individuals.

Mental health.
Five of the 25 quantitative studies evaluated the effects of elastic band resistance training on mental health in older adults [39,51,58,62,66].Some of these studies did not directly use dedicated scales to assess mental health but employed scales containing dimensions of mental health [39,51,58].
Park et al [39] used the South Korean version of the World Health Organization's Quality of Life questionnaire, which was divided into four main areas: physical health, psychological relations, social relations, and the surrounding environment.After the intervention, scores for psychological relations, social relations, and the surrounding environment showed statistically significant improvement.Damush et al [51] used the health-related quality of life (HRQOL) scale containing both mental and physical health functioning dimensions and observed no significant difference in changes in mental and physical health functioning compared to the control group.Chan et al [58] used the 12-Item Short-Form Health Survey, which measures participants' perceived health, both physical and mental.In terms of mental health, there was no significant difference.Jette et al [62] used the Mood State Scale specifically to assess and understand the emotional state of participants, which was divided into six dimensions: tension-anxiety, depression-dejection, vigor, fatigue, anger, and confusion.Compared with the control group, the elderly men in the experimental group experienced significantly less anger, less tension-anxiety, and significantly more vigor after the intervention.In addition, the study also used the Short Form 36 Health Survey Questionnaire, which revealed no improvement in mental health.Sanchez-Lastra et al [66] used the Spanish version of the Mini-Mental State Examination and Trail Making Test Part A to assess participants' mental state.The results showed that elastic band training can improve the cognitive function of elderly individuals.
Of the five studies on mental health, three interventions showed positive mental health benefits, and two interventions did not change, suggesting that the beneficial effects of elastic band resistance training on mental health in older adults are uncertain.

Qualitative evidence
Two qualitative studies and the qualitative portion of one study with a mixed approach explored the benefits, preferences and obstacles of elastic band resistance training in older adults.Two qualitative studies were conducted by Chen et al [55,56].The first study evaluated the feasibility of using a band resistance exercise regimen for older adults in wheelchairs [55].After four weeks of elastic band resistance training, elderly people in wheelchairs were interviewed using semi-structured questionnaires to discuss the simplicity, safety, suitability, and helpfulness of the training and put forward suggestions.The second study by Chen et al [56] evaluated the feasibility of a band exercise program for older adults and determined appropriate exercise frequency and preferences for older adults.The study was divided into two stages.In the first stage, experts evaluated the simplicity, safety, suitability, and helpfulness of the program, scored each exercise, and put forward suggestions for modification.In the second stage, after a one-month group training with the elastic band for elderly individuals, participants were interviewed individually to evaluate the simplicity, safety, suitability, and helpfulness of the training and put forward suggestions.A mixed-methods study by Rathleff et al [57] investigated the feasibility and acceptability of unsupervised elastic band training for frail elderly inpatients.On day 1, the patient received 30 minutes of practice instruction, after which an unsupervised stretch band exercise was performed once daily, and the performance of the exercise was checked on days 2 and 4. Semi-structured interviews were held with patients and ward staff the day before discharge and after intervention.
Participants in all three studies reported physical and mental benefits of band resistance training [55][56][57].After the intervention, participants felt that their muscles were more powerful in both their hands and legs, that they had increased body flexibility and joint range of motion, and they were more energetic and willing to continue participating in the stretch band exercises.
Participants also reported some preferences and barriers to training.In the first study by Chen et al [55], most participants tended to be placed in groups with 15 to 20 other participants, who engaged three times per week in 40 minutes of training.In the second study, most participants preferred to exercise in groups of 20 to 29 people for 1 hour 3 times a week.In addition, more than half of the participants preferred female coaches to lead them in the exercises [56].Patients in the study of Rathleff et al [57] reported no difficulty in understanding and performing these exercises,the training time was unlimited, and the elastic band was easy to use and store.The motivation for training was mainly because they thought the exercises would help them return to their previous level of functioning.In addition to the physical benefits, the staff found that the exercises encouraged patients to take greater responsibility for their lives, and through active communication with the patients, they could learn which daily activities the patients needed help with and which ones they could perform independently.They also found that patients needed a certain level of cognitive ability to carry out the exercises independently.Statements about the amount of training indicated that patients did not truly care about the number of repetitions of the training movements but were more interested in whether they had been training at all times.If the training process was disturbed, the training amount was greatly affected.

Integration of quantitative and qualitative evidence
The quantitative and qualitative evidence was integrated based on five questions used to integrate evidence in the JBI methodology of MMSR [36,37].The independent syntheses of the quantitative and qualitative studies partially supported each other.
Evidence from integrated quantitative studies showed that elastic band resistance training helped to improve mental health, upper and lower limb flexibility, endurance, upper strength, and enhanced physical balance and cardiopulmonary function in older people, which has also been partially empirically verified in qualitative studies.Qualitative studies indicate that band resistance training could improve mental health, hand and leg muscle strength, and physical flexibility in older adults.However, there is no evidence from qualitative studies that training improved physical balance and cardiorespiratory function in older adults.One reason may be that relevant questions were not included in semi-structured interviews for qualitative research.Therefore, these two aspects should be discussed in future qualitative research on resistance training with an elastic band.
In the integrated quantitative study, the frequency of intervention was approximately 2-5 times per week, 30 to 80 minutes each time, which is consistent with the exercise preference of the elderly determined in the qualitative study (it was 40 to 60 minutes three times per week).
The number of exercise groups, repetitions, and mean and total muscle activation times were monitored in the study by Rathleff et al [57].The results suggest that the current form of intervention was not feasible because few patients reached the standard training dose.However, qualitative evidence implies that patients and staff had a positive attitude toward the campaign.Future studies should adjust and refine interventions to improve patient adherence to exercise.

Effects on physical fitness and mental health
This mixed-methods systematic review pooled evidence from the quantitative and qualitative studies on the effects of elastic band resistance training on physical and mental health in older adults.The quantitative studies support the idea that training interventions in the elastic band group are effective in improving upper and lower limb flexibility, upper and lower limb endurance, upper strength, balance, and cardiopulmonary function in elderly individuals.The results are similar to studies of other types of resistance training such as with soft weights, ankle weights, and medicine balls, which indicate that resistance training improved balance and physical activity by increasing muscle mass, muscle strength, and bone density [67,68].Other studies used resistance training to achieve lipid reduction, and to improve blood sugar, blood pressure, blood lipids, lung capacity, muscle flexibility, and joint mobility function [69,70].Data from qualitative and quantitative studies are combined using established methods to increase the richness and robustness of the synthesis.In addition, by changing the thickness and length of the elastic band, the level of resistance training could be increased or decreased flexibly, expanding the range of application of elastic band resistance training, such as in frail elderly people, obese elderly people, and elderly people in wheelchairs [40,41,47].
Of the five quantitative studies, three showed positive effects on the mental health of older adults, and two showed no difference.In the qualitative studies, participants had a positive attitude toward resistance training with elastic bands and reported feeling more energetic in their daily activities after the intervention.Combined with the results of qualitative research, elastic band resistance training was an effective, safe and economical measure that was beneficial to the mental health of elderly individuals.The reason might be related to the improvement of physical function or social interaction of the elderly through exercise [50].Active exercise not only played an important role in reducing the onset of disease and increasing the independence of older people but also enhanced their self-esteem and body image, encouraged them to adopt a healthier lifestyle, and was an effective way of coping with stress.In addition, from a physiological point of view, the slow and gradual increase in the intensity of resistance training with elastic bands led to decreased sympathetic nerve output and increased happiness [51].However, due to the small number of studies on the improvement of mental health by resistance training with elastic bands, these results should be interpreted with caution.

Training preferences and obstacles
The quantitative part of Rathleff et al [57] found that few patients reached the standard training dose with unsupervised training, while the qualitative part found that patients did not truly care about the number of repetitions of training movements but were more interested in whether they were training all the time.Similar to previous findings, Liaghat et al [71] found that supervised training had potential benefits regarding quality of life, dropout, and training adherence.Dalager et al [72] found that supervision was not a significant predictor of compliance, but compared with the control group, the intervention effect of the supervision group was more significant.It is suggested that in the future resistance training, the support and supervision equipment of mobile technology should be applied, combined with remote sensing technology, remote control technology and information processing technology.In this way, individual elderly people can carry out personalized exercise guidance, functional training, evaluation and supervision, timely correction of irregular training movements, enhance training compliance, and improve exercise effects.In the first study by Chen et al [55], the majority of participants tended to take part in a group of 15 to 20 participants at a frequency of three times for 40 minutes per week.In the second study [56], it was found that most participants preferred the frequency of exercise for an hour three times a week in groups of 20 to 29 people.Some studies maintained that group intervention was an effective way to promote healthy behavior [73,74].The intervention process was conducive to peer support and communication, meeting the needs of interpersonal communication among elderly individuals, reducing loneliness, and promoting mental health.Group training can create cohesion, provide fun, and promote behavioral change, also known as a sense of belonging in a group [40].In addition, more than half of the participants preferred a female trainer to lead their workouts.They believed that a coach must be patient with the learner, and it would be better if it was someone they knew well.One reason might be that a familiar coach made participants less nervous, made it easier to establish a trusting relationship, and helped them feel more confident about the task, thus allowing them to engage in the exercise environment.At the same time, group training at a time convenient for participants could also improve the effect of the intervention.

Included study quality
This review used MMAT to assess the quality of the included studies, which varied from study to study.All studies had clear research questions, and the collected data could also answer the research questions.
For quantitative studies, the problems of randomized controlled studies focused on the random allocation method and blind implementation of outcome index evaluators.Ten randomized controlled studies did not introduce how to implement the random allocation method in detail but only mentioned randomness [43, 44, 49-52, 60-62, 64].Ten studies did not report on whether the outcome indicator evaluators were blinded [44, 45, 49-51, 59-61, 63, 64], and two studies mentioned that the outcome indicator evaluators were not blinded [40,53].In future studies, the random assignment method should be reported on in detail, and the outcome index evaluators should be blinded to improve study quality.In the inclusion of nonrandomized controlled studies, 4 studies did not take into account confounding factors that might affect the interpretation of the results, which could be improved in future research [42,48,58,66].For qualitative research, all quality evaluation criteria are satisfied [55,56].

Limitations
This review has some limitations.First, resistance training had many benefits for elderly individuals, not only in terms of mental health and physical fitness but also in terms of sleep quality, blood pressure, bone density, blood sugar in serum, total cholesterol, high-density lipoprotein, low-density lipoprotein, and other levels.However, integration failed due to the small number of relevant studies.Second, there were only two qualitative studies and one mixed-methods study, which limited the integration and analysis of the qualitative studies, thus requiring careful interpretation of the results from the qualitative evidence.Third, the number of quantitative studies assessing mental health was limited, the assessment tools were not targeted, and the results need to be interpreted with caution.Future studies should pay attention to the impact of elastic band resistance training on the mental health of elderly individuals.Fourth, due to the majority of quantitative studies in this systematic review, which also caused limitations for the integration of quantitative and qualitative evidence.It was suggested that qualitative research on elastic band resistance training should be strengthened in the future to supplement the views and suggestions of older people regarding this intervention.

Conclusion
Elastic band resistance training appears to be effective in improving mental health, upper and lower limb flexibility, endurance, upper strength, and enhancing balance and cardiopulmonary function in elderly individuals.Despite the limited number of qualitative studies, consistent with quantitative evidence, participants felt that elastic band resistance training can offer physical and mental benefits.The preferences and obstacles encountered in implementing elastic band resistance training were evaluated to provide a reference for future research.

3. 3 . 1 .
Physical fitness.3.3.1.1.Upper and lower limb flexibility.Twelve of the 25 quantitative studies measured the effects of elastic band resistance training on upper and lower limb flexibility in older adults.Six were randomized controlled trials

Table 1 .
(Continued) a This symbol means that multiple papers have been published in the same sample of participants.Abbreviations:CG, control group; EG, experience group; RCT, randomized controlled trial; HGS, Hand grip strength test; PSQI, Pittsburgh Sleep Quality Index; SF-12, 12-Item Short-Form Health Survey; TUG test, Time Up and Go Test; ABC scale, Activities-specific Balance Confidence scale; SRT,sit and reach test;6MWT, Six minute walking test; FRT, Functional Reach Test; BST, Back Scratch Test; TCR test,Timed chair rise test;sit and reach, Chair Sit and Reach Test; Arm Curl, 30-s Arm Curl Test ; SF-36, the short form 36 health survey questionnaire; POMS, Profile of Mood States https://doi.org/10.1371/journal.pone.0303372.t001

of study design: Quantitative Descriptive Screening question responses Methodological quality criteria responses
Upper limb strength.Grip strength mainly measures the development level of upper limb muscle groups.Among the 25 quantitative studies included, 16 measured the effect of elastic band resistance training on hand grip strength in elderly individuals.Four were nonrandomized controlled trials